All lines of inquiry were considered in the early stages of the investigation, says the Met Credit: Dominic Lipinski/PA Archive

A spokesman for the Metropolitan Police said:

"All lines of inquiry were considered in the early stages of the investigation. The investigation was detailed and complex and officers had a duty to explore every avenue of inquiry and retain an open mind about the circumstances.

An acid attack victim has told ITV's Daybreak that it remains a mystery why a 15-year-old boy carried out the assault.

Tara Quigley told Daybreak about the moment she was attacked. Credit: ITV Daybreak

Tara Quigley, 28, said she answered the door to the teenager, a stranger, who asked to speak to "Michelle" just before 9pm on April 30.

She said: "I was at home with my family. A young man knocked at my front door, asked me if my name was Michelle, to which I told him my name was Tara, so he left, quite abruptly. He came back about five minutes later and knocked again - as soon as I opened my front door, he threw the acid at me."

The 28-year-old managed to shut the door after the attack and rinse her face with water while an ambulance was called.

The 15-year-old pleaded guilty to a charge ofthrowing corrosive fluid on a person with intent to do grievous bodily harm and is due to be sentenced on Friday, a Scotland Yard spokesman said.

A woman who had acid thrown in her face as she opened her front door in Romford, London says she does not understand why a stranger attacked her and is appealing for anyone who may know something to contact police:

"I don't understand why this has happened to me. I feel devastated and am coming to terms with the fact I might have to bear the scars of this cowardly attack for the rest of my life.

"I was at home with my family at the time. It doesn't bear thinking about that this could have been one of the children instead of me as the man didn't even look up when threw it at me.